Background <p>Radical esophagectomy after neoadjuvant chemotherapy (NAC) is the established strategy for resectable advanced esophageal cancer. However, some patients are converted to definitive chemoradiotherapy (dCRT) after NAC due to reasons such as their wishes or disease progression, and their prognosis remains uncertain. This study aimed to investigate the prognosis of patients who converted to dCRT.</p> Methods <p>Patients who underwent NAC for resectable advanced esophageal squamous cell carcinoma between 2006 and 2020 were enrolled in this study retrospectively. The prognostic impact of subsequent treatment after NAC, planned surgery, or conversion to dCRT, was compared.</p> Results <p>The study analyzed 686 patients, 70 who were converted to dCRT (dCRT group) and 616 who underwent surgery (Surg group). The dCRT group had a poorer prognosis than the Surg group, with more advanced tumors and poorer response to NAC. Therefore, further analysis was performed by categorizing patients as Responders (complete or partial response) and Non-responders (stable or progressive disease) to NAC. Among the Responders in the dCRT group, 76.7 % achieved a complete response, and the 5-year esophageal preservation survival rate was 66.9 %. The 5-year survival rates for Responders were 77.5 % in the dCRT group and 71.3 % in the Surg group. Multivariable analysis showed that dCRT did not worsen prognosis (<i>P</i> = 0.706; hazard ratio, 1.13; 95 % confidence interval, 0.59–2.16). Conversely, among the Non-responders, dCRT had a significantly poorer prognosis, with 5-year survival rates of 22.3 % in the dCRT group and 45.1 % in the Surg group (P &lt; 0.001).</p> Conclusions <p>For patients responding to NAC, conversion to dCRT is considered a potential treatment option.</p>